Formulation Development of Azadirachta indica Extract as Nanosuppository to Improve its Intrarectal Delivery for the Treatment of Malaria.

BACKGROUND: Previous folkloric and experimental reports have demonstrated the antimalarial efficacy of Azadirachta indica (AZA) extracts. However, one of the major challenges facing its application for the clinical treatment of malaria is the design of an acceptable dosage form. OBJECTIVE: Consequently, we developed AZA extract-loaded nanostructured lipid carriers (NLC) for the formulation of suppositories, denoted as nanosuppositories, for intrarectal treatment of malaria. METHODS: Various batches of NLC-bearing AZA extract were formulated based on lipid matrices prepared using graded concentrations of Softisan®154 and Tetracarpidium conophorum or walnut oil. NLC was investigated by size and differential scanning calorimetry (DSC). Suppository bearing AZA extract-loaded NLC was developed using cocoa butter or theobroma oil, and their physicochemical properties were profiled. In vitro drug release and in vivo antimalarial activity (using Plasmodium berghei-infected mice) were investigated. RESULTS: NLCs exhibited sizes in nanometers ranging from 329.5 - 806.0 nm, and were amorphized as shown by DSC thermograms. Nanosuppositories were torpedo- or bullet- shaped, weighing 138 - 368 mg, softened/liquefied between 4.10 - 6.92 min, and had controlled release behaviour. In vivo antimalarial study revealed excellent antimalarial efficacy of the nanosuppositories comparable with a commercial brand (Plasmotrim®) and better than the placebo (unloaded nanosuppository), and without toxic alterations of hepatic and renal biochemical factors. CONCLUSION: Thus, AZA extract could be rationally loaded in nanostructured lipid carriers (NLC) for further development as nanosuppository and deployed as an effective alternative with optimum convenience for intrarectal treatment of malaria.

Solidified Reverse Micellar Solution- (SRMS-) Based Microparticles for Enhanced Oral Bioavailability and Systemic Antifungal Efficacy of Miconazole Nitrate in Immunocompromised Mice.

PURPOSE: To assess the improvement in oral bioavailability and efficacy in systemic candidiasis treatment of miconazole nitrate (MN) formulations in murine models of candidiasis. METHODS: Selected formulations containing 5% of Softisan + Phospholipon 90H lipid matrix with 3% of MN (A 1), 5% of stearic acid + Phospholipon 90H lipid matrix with 3% of MN (B 1), and 5% Softisan + stearic acid + Phospholipon 90H with 3% of MN (C 1) from the in vitro investigation were used for the study. Their acute toxicity was assessed using Lorke's method (with slight modification) while bioavailability was determined using the bioassay method. The optimized batch (A 1) was tested in murine systemic candidiasis induced in cyclophosphamide-immunosuppressed mice. The mice were treated with a single oral dose (100 mg/kg) of the formulations for five days. Serum fungal counts (cfu/mL) were determined on days 1, 3, and 5 of the treatment period. Haematological assessments were done. RESULTS: The lipid formulations were safer than MN powder with LD50 values of 3162.8 and 1118.3 mg/kg. Bioavailability determination revealed a higher area under the curve (AUC) value for formulations A 1 (6.11 µg/hr/mL) and B 1 (4.91 µg/hr/mL) while formulation C 1 (1.80 µg/hr/mL) had a lower AUC than MN (4.46 µg/hr/mL). Fungi were completely cleared from the blood of animals treated with the optimized formulation by day 3 as opposed to the controls (MN and Tween® 20) which still had fungi on day 5. No significant increase (p > 0.05) in haematological parameters was observed in mice treated with A 1. CONCLUSION: Formulation A 1 successfully cleared Candida albicans from the blood within a shorter period than miconazole powder. This research has shown the potential of orally administered MN-loaded SRMS-based microparticles in combating systemic candidaemia.

Development of lipid-based microsuspensions for improved ophthalmic delivery of gentamicin sulphate.

Aim: Anterior eye segment disorders are treated with eye drops and ointments, which have low ocular bioavailability necessitating the need for improved alternatives. Lipid microsuspension of gentamicin sulphate was developed for the treatment of susceptible eye diseases. Materials & methods: Lipid microsuspensions encapsulating gentamicin sulphate were produced by hot homogenization and evaluated. Ex vivo permeation and ocular irritancy tests were also conducted. Results & conclusion: Stable microsuspensions with high entrapment efficiency and satisfactory osmolarities were obtained. Release studies achieved 49-88% in vitro release at 12 h with sustained permeability of gentamicin compared with conventional gentamicin eye drop (Evril®). No irritation was observed following Draize's test. The microsuspensions have great potential as ocular delivery system of gentamicin sulphate.

Novel Intravaginal Drug Delivery System Based on Molecularly PEGylated Lipid Matrices for Improved Antifungal Activity of Miconazole Nitrate.

The aim of this study was to investigate the potential of microparticles based on biocompatible phytolipids [Softisan® 154 (SF) (hydrogenated palm oil) and super-refined sunseed oil (SO)] and polyethylene glycol- (PEG-) 4000 to improve intravaginal delivery of miconazole nitrate (MN) for effective treatment of vulvovaginal candidiasis (VVC). Lipid matrices (LMs) consisting of rational blends of SF and SO with or without PEG-4000 were prepared by fusion and characterized and employed to formulate MN-loaded solid lipid microparticles (SLMs) by melt-homogenization. The SLMs were characterized for physicochemical properties, anticandidal activity, and stability. Spherical discrete microparticles with good physicochemical properties and mean diameters suitable for vaginal drug delivery were obtained. Formulations based on SO:SF (1:9) and containing highest concentrations of PEG-4000 (4 %w/w) and MN (3.0 %w/w) were stable and gave highest encapsulation efficiency (83.05-87.75%) and inhibition zone diameter (25.87±0.94-26.33±0.94 mm) and significantly (p<0.05) faster and more powerful fungicidal activity regarding killing rate constant values (7.10 x 10-3-1.09 x 10-2 min-1) than commercial topical solution of MN (Fungusol®) (8.00 x 10-3 min-1) and pure MN sample (5.160 x 10-3 min-1). This study has shown that MN-loaded SLMs based on molecularly PEGylated lipid matrices could provide a better option to deal with VVC.